1. Technical Field
The present invention relates to an inertia latch mechanism for latching an actuator of a disk drive device when an impact is applied from the outside to the disk drive device, and more particularly, to an installation structure of an inertia lever for use in the inertia latch mechanism.
2. Description of the Related Art
In the disk drive device in recent years, for the purpose of preventing sticking of a head slider to a surface of a disk and enhancing a reliability for an impact applied thereto, a load/unload mechanism for the head slider has been employed. During nonoperation of the disk drive device, the load/unload mechanism allows a part called a ramp, which is provided in the vicinity of an outer circumference of a disk, to hold an actuator, and thus allows the head slider to be escaped in no contact with a disk surface.
Meanwhile, in a disk drive device mounted on a portable personal computer (PC) of a notebook type or the like, a high reliability for the impact during non-operation has been required. During the non-operation of the disk drive device, if the head slider mounted on the actuator moves (pops out) from an escape position to a data area on the disk surface by the impact, then the head slider is stuck to the surface of the data area, or damages the surface of the data, resulting in a fatal failure. In order to obtain a high reliability for the impact during the non-operation, it is important to hold the actuator in the escape position and to prevent the actuator from swinging and moving to the surface of the data area by the impact during the non-operation.
The same can be said for the disk drive device using the load/unload mechanism. For an impact at a relatively low level, the ramp can prevent the head slider from popping out (loading). Specifically, the ramp constitutes a lock mechanism of the actuator for driving the head slider. However, for a large impact, it is difficult for only the lock mechanism formed of the ramp to prevent the actuator from popping out. Therefore, in many cases, besides the ramp, the disk drive device has an inertia latch mechanism provided therein.
The inertia latch mechanism operates when an impact is applied to the disk drive device. This latch mechanism is a mechanism for latching the actuator by use of inertia force generated by the applied impact. The inertia latch mechanism has a feature capable of latching the actuator for the strong impact.
For example, in the gazette of Japanese Patent Laid-Open No. Hei 10 (1998)-302418 (Japanese Patent No. 3077897, U.S. Pat. No. 6,163,440) by the applicants of the present application, an inertia latch mechanism is described. This inertia latch mechanism is basically constituted of a latch lever and an inertia lever in which an inertial moment is larger than that of the latch lever. When an impact swinging the actuator in a first direction is applied, this inertia lever swings to the first direction, engages with the latch lever at a first engaging portion, moves the latch lever to an actuator latching position, and allows the actuator to be latched. Moreover, when an impact swinging the actuator in a second direction is applied, the inertia lever swings to the second direction, engages with the latch lever at a second engaging portion, moves the latch lever to the actuator latching position, and allows the actuator to be latched.
As described above, the inertia lever performs a swing motion. In the conventional disk drive device, a pin erected in a case thereof has been set as a swing shaft.
However, work of erecting a pin as this swing shaft is not easy. Particularly, in a small size disk drive device mounted on the portable PC, since the pin itself is in small diameter, workability therefor is poor, and a position of erecting the pin must be determined with high accuracy. Once the pin is erected, correction cannot be made therefor. Meanwhile, in the inertia lever, a through hole for inserting the erected pin therethrough is drilled, and high accuracy is required for this through hole. For the reasons as described above, the inertia latch mechanism has hindered reduction in fabrication cost of the hard disk drive.